This invention relates to manual control devices for elevators and the like and is particularly directed to means for manually controlling the brake of a vertical plunger elevator.
As is well known, passenger elevators are typically raised or lowered by a cable which runs over a pulley located at the top of the elevator shaft. The elevator car is attached to one end of the cable, while a counterweight, equal to the weight of the elevator car plus several passengers, is attached to the opposite end of the cable. The car and counterweight run up and down the shaft on guide rails and an electric motor, needing only enough power to raise the difference in weight between the car and the counterweight, drives the pulley to move the car. When the car is stopped, for example, at a desired floor, a hoist brake acts to hold the car at the desired location. The hoist brake is typically urged into the locking position by springs and is released by a solenoid. Many prior art elevator brakes employ solenoids which have horizontal brake actuating plungers, which are urged outwardly by heavy springs to force the brake shoes into the licking position, while the solenoid acts to pull the plungers inwardly to release the brake. A device for manually controlling these horizontal plunger brake devices is disclosed in my copending patent application Ser. No. 08/753,190, filed Nov. 21, 1996. However, many other elevator brakes employ vertical solenoids having generally T-shaped plungers which drive a pair of rocker arms to force pivotally mounted brake shoes apart to release the brake, while strong springs normally urge the brake shoes toward each other to clamp the brake therebetween and, hence, to retain the elevator in a given position. The present invention enables an operator to manually control these vertical plunger brakes. A power outage often serves to set the brake to safely lock the car wherever it is within the elevator shaft until power is restored. Unfortunately, electrical or power failure prompting this emergency braking action often results in passengers being trapped in the elevator car at a location between floors until rescue personnel can open the shaft doors and reach the elevator car by ropes or ladders or moving another elevator car along side to remove the trapped passengers. However, this involves considerable time and risk for the passengers. Furthermore, such time-consuming rescues require a plurality of rescue personnel and demand that the passengers crawl through a trap door onto the roof of the elevator car in order to reach the ropes or ladders or an adjacent elevator car. However, this may be difficult or impossible for some passengers, especially those who are obese, elderly or handicapped. More importantly, in natural emergencies, it may be a considerable time before a sufficient number of rescue personnel are available to effect such rescues, which are time consuming in themselves. Obviously, the longer the wait for rescue, the greater is the peril from fire, smoke and aftershocks. Furthermore, where the power outage has been caused by an earthquake, there is danger or aftershocks which may dislodge chunks of concrete or other structural material within the elevator shaft, causing increased danger to both the rescuers and to the evacuating passengers. Clearly, it would be desirable to provide apparatus which would enable a single individual to effect a controlled release of the hoist brake to facilitate prompt rescue of trapped passengers. Apparatus for accomplishing one man release and control of elevator hoist brakes have been proposed heretofore. However, prior art elevator hoist brake release devices serve to fully release the elevator brake, allowing the car to xe2x80x9cdriftxe2x80x9d uncontrollably and at constantly increasing speeds, which are difficult to stop and which actually increase the danger to the passengers. Thus, none of the prior art elevator brake release devices have been entirely satisfactory.
These disadvantages of the prior art are overcome with the present invention and an improved elevator hoist brake control device is proposed for use on elevators having vertical plunger solenoids which device is simple and inexpensive to produce and purchase, yet which enables a single individual to quickly and easily release an elevator hoist brake in a controlled manner to permit safely xe2x80x9cdriftingxe2x80x9d the elevator car in a controlled, constant and predictable manner to an adjacent floor to allow trapped passenger to escape.
The advantages of the present invention are preferably attained by providing improved apparatus for manually releasing and controlling an elevator hoist brake having a solenoid with a vertically-actuated, flanged plunger operable to drive the brake shoes apart in opposition to brake springs which normally urge the brake shoes into the locking position, said apparatus comprising a bar having one end insertable between said solenoid and the flange of said plunger and engageable therewith, a handle having an enlarged portion projecting downwardly adjacent the forward end which is pivotally secured to said bar at a point spaced from said one end of said bar, a lever pivotally attached to said bar and having a forward end located adjacent said one end of said bar and dimensioned to be insertable between said solenoid and said flange of said plunger and engageable therewith, a link member pivotally connected to said bar at a point spaced from the forward end of said link and from said one end of said bar and having said forward end of said link pivotally connected adjacent the rear end of said lever, said link being formed with a longitudinal slot adjacent the rear end of said link member, and a bolt fixedly secured to said handle and extending through said slot of said link member whereby vertical movement of said handle will cause opposite vertical movement of said forward end of said lever to force said plunger outwardly from said solenoid.
Accordingly, it is an object of the present invention to provide an improved device for controlling elevator hoist brakes.
Another object of the present invention is to provide an improved elevator hoist brake control device for use on elevators having vertical plunger solenoids.
A further object of the present invention is to provide an improved elevator hoist brake for use on elevators having vertical plunger solenoids which device is simple and inexpensive to produce and purchase.
Another object of the present invention is to provide an improved elevator hoist brake control device for use on elevators having vertical plunger solenoids which enables a single individual to quickly and easily release said elevator hoist brake in a controlled manner to permit safely xe2x80x9cdriftingxe2x80x9d the elevator car in a controlled, constant and predictable manner to an adjacent floor to allow trapped passenger to escape.
A specific object of the present invention is to provide improved apparatus for manually releasing and controlling an elevator hoist brake having a solenoid with a vertically-actuated, flanged plunger operable to drive the brake shoes apart in opposition to brake springs which normally urge the brake shoes into the locking position, said apparatus comprising a bar having one end insertable between said solenoid and the flange of said plunger and engageable therewith, a handle having an enlarged portion projecting downwardly adjacent the forward end which is pivotally secured to said bar at a point spaced from said one end of said bar, a lever pivotally attached to said bar and having a forward end located adjacent said one end of said bar and dimensioned to be insertable between said solenoid and said flange of said plunger and engageable therewith, a link member pivotally connected to said bar at a point spaced from the forward end of said link and from said one end of said bar and having said forward end of said link pivotally connected adjacent the rear end of said lever, said link being formed with a longitudinal slot adjacent the rear end of said link member, and a bolt fixedly secured to said handle and extending through said slot of said link member whereby vertical movement of said handle will cause opposite vertical movement of said forward end of said lever to force said plunger outwardly from said solenoid.
These and other objects and features of the present invention will be apparent from the following detailed description, taken with reference to the figures of the accompanying drawing.